ALKYL GLUCOSIDE, ITS USE FOR CLEANING PURPOSES, AND CLEANING COMPOSITION

Abstract: In an alkyl glucoside of the formula (I): RCH2O(G)xH, R is an alkyl group having a total of 8-12 carbon atoms and containing 2-4 groups of formula -CH(CH3)- in its carbon chain; G is a monosaccharide residue; and x is 1-4. The use of the alkyl glucoside as a surfactant in the cleaning of hard surfaces is also disclosed. A composition containing an alkyl glucoside of formula (I), a complexing agent and a solubiliser is further described.

Description: ALKYL GLUCOSIDE, ITS USE FOR CLEANING PURPOSES, AND CLEAN¬ ING COMPOSITION This invention relates to an alkyl glucoside in which the alkyl group is methyl-branched, as well as the use of the alkyl glucoside as a surfactant in the cleaning of hard surfaces. The invention also concerns a cleaning composition in which the alkyl glucoside is combined with a solubiliser and preferably also with a complexing agent. In recent years, attention has focused on alkyl glu¬ cosides, since these have proved to be more easily bio¬ degradable than other non-ionic surfactants, such as ethy- lene oxide adducts of fatty alcohols. US Patent Specifica¬ tion 3,839,318 thus describes the production of alkyl glu- cosides and alkyl oligosaccharides, such as n-octyl gluco¬ side, n-hexyl glucoside, n-decyl glucoside, n-dodecyl glu¬ coside, isodecyl glucoside, isoundecyl glucoside, isotri- decyl glucoside and the corresponding oligosaccharides. The United States Stationary Invention Registration H171 states that alkyl glucosides of formulae R(0G) and R(OG) are excellent surfactants. In these formulae, R is an alkyl or alkenyl group which is branched at the second carbon atom or at a higher carbon atom, the branch being selected from the group methyl, ethyl, isopropyl, n-pro- pyl, butyl, pentyl, hexyl and mixtures thereof, provided that R contains from about 7 to about 30 carbon atoms; G is a saccharide group selected from the group glucose, fructose, mannose, galactose, talose, allose, altrose, idose, arabinose, xylose, lyxose, ribose and mixtures thereof; and x is 2 or more. Example 1 contains a descrip¬ tion of the production of two product mixtures substan¬ tially made up of 2-ethylhexyl glucoside and isooctyl glu¬ coside, respectively. DE 20 36 472, EP 306 650, EP 306 651 and EP 366 652, inter alia, also describe alkyl glucosides. Even though alkyl glucosides generally are easily biodegradable, they are only used to a limited extent in many ranges of application, such as the cleaning of hard surfaces, since they are too high-foaming and/or have too poor a cleaning power. It is therefore a desideratum to provide non-ionic surfactants which are about as easily biodegradable, but which have a better cleaning effect on hard surfaces and/or are more low-foaming than known alkyl glucosides. According to the present invention, it has now sur¬ prisingly been found that an alkyl glucoside of formula wherein R is an alkyl group having a total of 8-12 carbon atoms and containing 2-4 groups of formula -CH(CH«)- in its carbon chain, G is a monosaccharide residue, and x is 1-4, is advantageously used as a surfactant in composi¬ tions for cleaning hard surfaces. The alkyl glucoside of formula I shows good cleaning and wetting properties, as well as low foaming compared with other alcohols of approximately the same chain length. In addition, the alkyl glucoside has proved to be easily degradable and have low biotoxicity. Tests have not shown any skin irritations caused by the alkyl glucosides. Preferably, there are 2 or 3 methyl groups. Compounds in which R con¬ tains 9 or 10 carbon atoms and x is 1 or 2 are especially preferred, having a good cleaning power and being compara¬ tively easy to produce. The compounds according to the invention can be pro¬ duced in conventional manner by reacting an alcohol of formula RCH 2 0H (II) wherein R is as indicated above, with a monosaccharide in the presence of an acid catalyst, the molar ratio of the alcohol to the monosaccharide being 2:1-80:1. The catalyst may be an inorganic or organic acid. The reaction is per- formed under vacuum at 90-120°C for about 1-4 h. Conve¬ niently, the resulting reaction mixture is first filtered and then neutralised with an organic and/or an inorganic base, whereupon excess alcohol is carefully removed e.g. by distillation, if so desired. The alcohols of formula (I) can be produced in con¬ ventional manner by condensing propene, butene or mixtures thereof, whereupon the di-, tri- or tetramers obtained are prolonged with a carbon atom by the oxoprocess. The resulting aldehydes may then easily be converted to the corresponding alcohols. The alcohols obtained form a com¬ plex mixture of methyl-branched structures, although some ethyl substituents may be present. The amount of quater¬ nary carbon found in the carbon chain is very small, and alcohols containing quaternary carbon are to be regarded as impurities not encompassed by the invention. Examples of suitable alcohols are Exxal 9, Exxal 10, Exxal 11, Exxal 12 and Exxal 13, all sold by Exxon Chemical. The monosaccharide used as reactant suitably consists of pen- tose and hexose. Specific examples of monosaccharides used in the production of the inventive glucosides are glucose, mannose, galactose, talose, allose, altrose, idose, arabi- nose, xylose, ribose and lyxose. Glucose is usually pre¬ ferred for commercial reasons. The alkyl glucosides according to the invention are suitable for use in compositions for cleaning hard sur¬ faces, e.g. for degreasing such surfaces or washing up. Excellent results are obtained in the degreasing of lac¬ quered or unlacquered metal surfaces. Apart from the inventive alkyl glucoside, these compositions preferably contain a water-soluble solubiliser and suitably contain a complexing agent. Examples of solubilisers are alkyl ether polyalkylene glycol, such as monobutyl diethylene glycol; glycols, such as diethylene glycol, dipropylene glycol and propylene glycol; alcohols, such as ethanol, propanol and iso- propanol; alkyl glucosides in which the alkyl group has 4-8 carbon atoms; and/or tertiary or quaternary amine alkoxylates in which the alkyl group, which may be straight or branched, saturated or unsaturated, has 8-20 carbon atoms and in which 6-30 mol of alkylene oxide is added per mol of amine. Preferably, 50-100 mol per cent of the added alkylene oxide consists of ethylene oxide, the remainder preferably consisting of propylene oxide or a mixture of propylene oxide and butylene oxide. The diffe¬ rent alkylene oxides can be added randomly or in blocks. If the cleaning composition should be exceptionally low- foaming, the alkylene oxide chain conveniently ends with an addition of 1-5 mol of propylene oxide and/or butylene oxide. The ratio of the solubiliser to the inventive alkyl glucoside is usually 1:10-5:1, preferably 1:3-3:1. The complexing agent may be a conventional inorganic or organic agent, such as an inorganic phosphate or NTA, EDTA, citric acid or a polycarboxylate. The amount added may vary from nothing at all to 300% by weight of the inventive alkyl glucoside. Preferably, the quantitative ratio of the complexing agent to the alkyl glucoside is 1:10-2:1. The cleaning compositions may further contain other additives, such as pH-adjusting agents, antifoaming agents, enzymes, other surfactants and scents. The com- positions are usually aqueous and in the form of emul¬ sions, microemulsions or solutions. The invention will now be further illustrated by a few Examples. Example 1 An alkyl glucoside was produced by reacting 2.6 mol of an alcohol (Exxal 9) of formula (II), wherein R is a C g alkyl having a methyl substitution of about 2 (average value), with 0.4 mol of glucose in the presence of 0.015 mol of sulphuric acid as catalyst at 110°C and 70 mbar. The reaction was interrupted after 105 min. The resulting product mixture was treated by distilling off excess alco¬ hol under vacuum. The yield was 105 g, consisting of 60% of C q -branched alkyl monoglucoside, 15% of C 8 -branched alkyl diglucoside and a residue of higher oligomers. The glucosides had an average degree of polymerisation (DP) of about 1.5. The structure was determined by gas chro ato- graphy, mass spectrometry and NMR. Example 2 An alkyl glucoside was produced by reacting 7.6 mol of an alcohol (Exxal 10) of formula (II), wherein R is a Cg alkyl having a methyl substitution of about 2.2 (average value), with 1.2 mol of glucose in the presence of 0.015 mol of sulphuric acid as catalyst at 90-111°C and 100 mbar. The reaction was interrupted after 120 min. The reaction mixture was treated by distilling off excess alcohol under high vacuum. The yield was 278 g, consisting of 60% of monoglucoside, 12% of diglucoside and a residue of higher oligomers. The glucosides had an average DP of 1.6. Example 3 Here, 20 ml of each of the cleaning compositions below, diluted with 10 parts by weight of water per part by weight of the composition, was applied on a vertically arranged iron sheet soiled with mineral oils, soot, salts and clay. After application, the coated surface was rinsed with water without any mechanical treatment. Components Composition, % by weight 1 2 A B C D E Glucoside (Example 1) 5 Glucoside (Example 2) 5 Glucoside A 5 Glucoside B 5 Glucoside C 5 Glucoside D 5 Butyldiethylene glycol 11 11 11 11 11 Quaternary ethoxy- lated fatty amine (Berol 555) 4 4 NTA 5 5 3 3 3 3 5 Water 86 86 81 81 81 81 84 Glucoside A = 2-ethylhexyl-0(G) H Glucoside B = isooctyl-O(G) H Glucoside C = n-dodecyl/n-tetradecyl glucoside (APG-600, Henkel) Glucoside D = n-decyl glucoside (Lutensol GD-70, BASF) wherein G = glucoside residue and x = 1.5 (average value). The attained cleaning effect was assessed with respect to the area of the cleaned surface, as well as its actual cleanness, the figure 1 indicating no improve¬ ment and the figure 10 indicating a perfectly clean sur¬ face. The following results were obtained. 2 Composition Cleaned surface, cm Cleanness 1 112 6 2 144 8 A 0 1 B 80 4 C 48 6 D 72 6 E 0 1 The foaming of the different ready-to-use solutions was measured according to Ross-Miles ASTM D 1173-53. The following results were obtained. Foam height, mm Composition Instantaneously After 5 min 1 5 0 2 8 0 A 7 0 B 20 3 C 67 63 D 46 45 It is evident from these results that the alkyl glucosides according to the invention show an excellent cleaning power and are clearly superior to alkyl gluco¬ sides having a straight carbon chain with 10-14 carbon atoms, while at the same time having an acceptable degree of foaming. The composition containing alkyl glucosides having an alkyl group with 8 carbon atoms showed an unsatisfactory cleaning power.

Claims: C L I M S 1. The use of an alkyl glucoside of the general for¬ mula RCH 2 0(G) χ H (I) wherein R is an alkyl group having a total of 8-12 carbon atoms and containing 2-4 groups of formula -CH(CH 3 )- in its carbon chain; G is a monosaccharide residue; and x is 1-4, as a surfactant for cleaning hard surfaces. 2. Use as set forth in claim 1, c h a r a c t e r ¬ i s e d in that R is an alkyl group having 9 or 10 carbon atoms. 3. Use as set forth in claim 1 or 2, c h a r a c ¬ t e r i s e d in that R has a methyl substitution of 2 or 3. 4. Use as set forth in claim 1, 2 or 3, c h a r a c - t e r i s e d in that G is a glucose residue. 5. Use as set forth in any one of claims 1-4, c h a ¬ r a c t e r i s e d in that x is 1 or 2. 6. Use as set forth in claims 1-5 of the alkyl gluco¬ side of formula (I) as a surfactant in a cleaning composi- tion for degreasing lacquered or unlacquered metal sur¬ faces. 7. A cleaning composition, c h a r a c t e r i s ¬ e d in that it contains, in addition to the alkyl glu¬ coside of formula (I), a water-soluble solubiliser and, optionally, an organic or inorganic complexing agent. 8. A cleaning composition as set forth in claim 7, c h a r a c t e r i s e d in that the solubiliser con¬ sists of alkyl ether polyglycols, glycols, alcohols and/or tertiary and/or quaternary alkylamine alkoxylates. 9. A cleaning composition as set forth in any one of claims 6-8, c h a r a c t e r i s e d in it contains a solubiliser in an amount of 1:3-3:1 based on the weight of the alkyl glucoside, and a complexing agent in an amount of 1:10-2:1 based on the weight of the alkyl glucoside. 10. An alkyl glucoside of the general formula RCH 2 0(G) χ H (I) wherein R is an alkyl group having a total of 8-12 carbon atoms and containing 2-4 groups of formula -CH(CH^)- in its carbon chain; G is a monosaccharide residue; and x is 1-4.

Inventors: JOHANSSON INGEGAERD, JOHANSSON, INGEGAERD
Applicants: BEROL NOBEL AB, JOHANSSON INGEGAERD, JOHANSSON, INGEGAERD
Application year: 1994
Main classification: C11D1
IPC codes: A61K8, A61Q5, A61Q19, C07H15, C11D1, C11D3, C23G1